There’s been a lot of talk lately that the U.S. average corn yield will set a new record this year, which has been fueled by favorable growing conditions and the crop rated in good or excellent condition. And those high crop ratings are contributing to the continued sliding price for corn.

“Expectations of a U.S. average corn yield above trend value in 2014 seem justified by current crop condition ratings. A yield above trend by as much as the average (14.1 bushels) of the previous six highest yielding years since 1960 would be 173.6 bushels per acre. However, June weather conditions in Illinois, Indiana, and Iowa were not entirely consistent with those experienced in the previous six highest yielding years relative to trend. This was particularly true for Iowa, which received over twice its long-term average precipitation in June. There is no historical precedent in the last five decades for an extremely high corn yield relative to trend (1972, 1979, 1982, 1985, 1986, 1987, 1994, 2004, and 2009) when Illinois, Indiana, or Iowa had such an extreme amount of precipitation during June. The same conclusion also holds when other major corn-producing states are included in the analysis. This does not mean that such an exception cannot occur, but it would be unprecedented. On the other hand, it should also be pointed out that weather in the first six days of July was very favorable for corn yield prospects. Temperatures in major corn producing states averaged two to seven degrees below normal and precipitation was near average over a widespread area. Near average precipitation and below average temperatures are expected over the next two weeks. Such weather would keep expectations of a very high average corn yield alive. History suggests that cool, moist conditions need to persist through August for the U.S. average yield to be equivalent to that of the other high yielding years examined in this article.